Feedback design for multi-transmission reception point transmission

ABSTRACT

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a configuration message configuring the UE to communicate coordinated transmissions with multiple transmission reception points (TRPs) using a first coordinated transmission mode of a set of different coordinated transmission modes. The UE may receive, based on the configuration message, downlink control information including at least one indicator and receive a first coordinated transmission communicated in accordance with the first coordinated transmission mode. The UE may transmit, in accordance with a feedback configuration corresponding to the at least one indicator and the first coordinated transmission mode, a feedback message for the first coordinated transmission to at least one of the multiple TRPs.

CROSS REFERENCE

The present application for patent is a continuation of U.S. patentapplication Ser. No. 16/457,532, filed Jun. 28, 2019, which claims thebenefit of U.S. Provisional Patent Application No. 62/694,959 by YANG etal., entitled “FEEDBACK DESIGN FOR MULTI-TRANSMISSION RECEPTION POINTTRANSMISSION,” filed Jul. 6, 2018, the contents of which areincorporated herein by reference in their entirety.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to multi-transmission reception point (multi-TRP)transmission.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform-spread-orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

In some cases, a UE may communicate with two or more base stations(e.g., two or more transmission reception points (TRPs)) over time andfrequency resources dedicated for communications between the TRPs andthe UE. The TRPs may coordinate different configurations for thecommunications using backhaul links with minimal or zero delay. The TRPsand UE may have multiple different configurations for communication,which the TRPs may coordinate using backhaul links. Such coordinationtechniques, however, for the different configurations between the UE andthe TRPs may introduce latency and increase signaling overhead.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support feedback design for multi-transmissionreception point (multi-TRP) transmission. Generally, the describedtechniques provide for coordinating communication between a set oftransmission reception points (TRPs) and a user equipment (UE) thatenables the UE to identify a configuration to use for transmittingfeedback to at least one of the TRPs based on downlink control signalingand a coordinated transmission mode in which the UE is configured tooperate.

In an example, a first TRP of the set of TRPs may transmit aconfiguration message for configuring a UE to communicate coordinatedtransmissions with the set of TRPs. The configuration message mayindicate a first coordinated transmission mode of a set of differentcoordinated transmission modes. Each coordinated transmission mode mayindicate a number of uplink and downlink control channels and a numberof uplink and downlink data channels configured for communicationbetween a particular TRP and the UE. The first TRP may transmit, basedon the configuration message, downlink control information (DCI) thatincludes at least one indicator and a grant of resources for a downlinkcoordinated transmission from one of the TRPs to the UE.

In some cases, the DCI may include a downlink assignment index (DAI)indicator, an acknowledgment (ACK) or negative acknowledgment (NACK)(e.g., ACK/NACK) resource indicator (ARI), and a feedback gap indicator(e.g., a K1 value) which corresponds to a time gap between a physicaldownlink shared channel (PDSCH) message and when the UE is expected tosend a corresponding physical uplink control channel (PUCCH) messagecarrying a feedback message for the PDSCH message. Based on thecombination of DAI, ARI, and the feedback gap indicator, the UE maydetermine a feedback configuration for transmitting a feedback message(e.g., a hybrid automatic repeat request (HARM) message such as aHARQ-ACK or HARQ-NACK message) within a PUCCH message. The feedbackconfiguration may indicate the number of ACK/NACK bits in the feedbackmessage, the number of PUCCH resources allocated for reporting ACK/NACKfeedback, the number of TRPs, to which TRPs the UE is to transmit thefeedback message, or any combination thereof.

The UE may monitor the resources indicated in the grant and receive thecoordinated transmission communicated in accordance with the configuredtransmission mode. The UE may determine whether it is able tosuccessfully decode the coordinated transmission, and may transmit, inaccordance with the feedback configuration corresponding to the at leastone indicator and the first coordinated transmission mode, the feedbackmessage for the coordinated transmission. According to some aspects, theUE may determine the feedback configuration without the TRP having toincur additional signaling overhead of explicitly indicating thefeedback configuration to the UE.

A method of wireless communication at a UE is described. The method mayinclude receiving a configuration message configuring the UE tocommunicate coordinated transmissions with a set of TRPs using a firstcoordinated transmission mode of a set of different coordinatedtransmission modes, receiving, based on the configuration message, DCIincluding at least one indicator, receiving a first coordinatedtransmission communicated in accordance with the first coordinatedtransmission mode, and transmitting, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one of the set of TRPs.

An apparatus for wireless communication at a UE is described. Theapparatus may include a processor, memory in electronic communicationwith the processor, and instructions stored in the memory. Theinstructions may be executable by the processor to cause the apparatusto receive a configuration message configuring the UE to communicatecoordinated transmissions with a set of TRPs using a first coordinatedtransmission mode of a set of different coordinated transmission modes,receive, based on the configuration message, DCI including at least oneindicator, receive a first coordinated transmission communicated inaccordance with the first coordinated transmission mode, and transmit,in accordance with a feedback configuration corresponding to the atleast one indicator and the first coordinated transmission mode, afeedback message for the first coordinated transmission to at least oneof the set of TRPs.

Another apparatus for wireless communication at a UE is described. Theapparatus may include means for receiving a configuration messageconfiguring the UE to communicate coordinated transmissions with a setof TRPs using a first coordinated transmission mode of a set ofdifferent coordinated transmission modes, receiving, based on theconfiguration message, DCI including at least one indicator, receiving afirst coordinated transmission communicated in accordance with the firstcoordinated transmission mode, and transmitting, in accordance with afeedback configuration corresponding to the at least one indicator andthe first coordinated transmission mode, a feedback message for thefirst coordinated transmission to at least one of the set of TRPs.

A non-transitory computer-readable medium storing code for wirelesscommunication at a UE is described. The code may include instructionsexecutable by a processor to receive a configuration message configuringthe UE to communicate coordinated transmissions with a set of TRPs usinga first coordinated transmission mode of a set of different coordinatedtransmission modes, receive, based on the configuration message, DCIincluding at least one indicator, receive a first coordinatedtransmission communicated in accordance with the first coordinatedtransmission mode, and transmit, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one of the set of TRPs.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a number ofinformation bits for the feedback message and a number of PUCCHtransmissions in which to transmit the feedback message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the at least one indicatorincludes a DAI indicator, a feedback resource indicator, a feedback gapindicator, or any combination thereof.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that the atleast one indicator includes a first resource indicator indicating afirst PUCCH resource in a time interval and a second resource indicatorindicating a second PUCCH resource in the time interval that may bedifferent than the first PUCCH resource, where the feedback message maybe transmitted via each of the first PUCCH resource and the second PUCCHresource within the time interval.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the time interval may be aslot or a mini-slot.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying that theconfiguration message indicates that a PUCCH resource includes a firstresource having first quasi co-location (QCL) information and a secondresource having second QCL information, where the feedback message maybe transmitted via the first resource in accordance with the first QCLinformation and the feedback message may be transmitted via the secondresource in accordance with the second QCL information.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that the atleast one indicator includes a feedback resource indicator indicating afirst PUCCH resource and a second PUCCH resource that may be differentthan the first PUCCH resource, where the feedback message may betransmitted via the first PUCCH resource and via the second PUCCHresource.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the DCI further mayinclude operations, features, means, or instructions for receiving,within a same time interval, a first control channel transmissionincluding the DCI from a first TRP of the set of TRPs and a secondcontrol channel transmission including second DCI from a second TRP ofthe set of TRPs, the second DCI including a second at least oneindicator, determining, based on the first coordinated transmissionmode, that the first control channel transmission schedules the firstcoordinated transmission and that the second control channeltransmission schedules a second coordinated transmission, determiningthat the first coordinated transmission and the second coordinatedtransmission each include a same at least one codeword and a same atleast one feedback process identifier associated with the at least onecodeword, and determining that a number of information bits in thefeedback message is the same as the number of codewords scheduled by theDCI.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining to transmitthe feedback message for the first coordinated transmission and thesecond coordinated transmission in a single PUCCH transmission based ona first feedback gap indicator and a first feedback resource indicatorincluded in the at least one indicator being the same as a secondfeedback gap indicator and a second feedback resource indicator includedin the second at least one indicator.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the DCI further mayinclude operations, features, means, or instructions for determining totransmit the feedback message for the first coordinated transmission andthe second coordinated transmission in multiple PUCCH transmission basedon at least one of a first feedback gap indicator or a first feedbackresource indicator included in the at least one indicator differing froma second feedback gap indicator or a second feedback resource indicatorincluded in the second at least one indicator.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the DCI schedules one or twocodewords.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the firstcoordinated transmission communicated in accordance with the firstcoordinated transmission mode further may include operations, features,means, or instructions for determining whether to decode the firstcoordinated transmission received from the first TRP based on a decodingdecision for the second coordinated transmission received from thesecond TRP.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the DCI further mayinclude operations, features, means, or instructions for receiving,within a same time interval, a first control channel transmissionincluding the DCI from a first TRP of the set of TRPs and a secondcontrol channel transmission including second DCI from a second TRP ofthe set of TRPs, the second DCI including a second at least oneindicator, determining, based on the first coordinated transmissionmode, that the first control channel transmission schedules the firstcoordinated transmission and that a second control channel transmissionschedules a second coordinated transmission and determining that thefirst coordinated transmission and the second coordinated transmissioneach include a different codeword and a different feedback identifierassociated with each of the different codewords.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining tomultiplex or bundle information bits corresponding to each of the firstand second coordinated transmissions in a single PUCCH transmissionbased on determining that a first feedback gap indicator included in theat least one indicator may be the same as a second feedback gapindicator included in the second at least one indicator.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining tomultiplex or bundle information bits may be based on the configurationmessage.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying a feedbackresource for transmitting the feedback resource based on a feedbackindicator and a DAI indicator included in the at least one indicatorassociated with a defined monitoring occasion of the set of physicaldownlink control channel (PDCCH) monitoring occasions.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the ordering of the set ofPDCCH monitoring occasions corresponds to an ordering of a set ofcontrol resource set identifiers indicated in the configuration message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, each of the set of controlresource set identifiers may be respectively associated with the set ofPDCCH monitoring occasion, and where each control resource set of a setof control resource sets corresponds to one of the set of controlresource set identifiers and one of the TRPs.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining to transmitthe feedback indicator in multiple PUCCH transmissions based on a firstfeedback gap indicator included in the at least one indicator differingfrom a second feedback gap indicator included in the second at least oneindicator.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a PUCCHresource indicated by a feedback resource indicator of the at least oneindicator, identifying QCL information for the PUCCH resource anddetermining a number of TRPs to which the UE may be to transmit thefeedback message based on the QCL information.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that aPUCCH transmission including the feedback message may be to betransmitted to a single TRP of the set of TRPs based on the QCLinformation indicating that the PUCCH resource may have a QCLrelationship with a single downlink reference signal and transmit thefeedback message in accordance with the QCL information for the PUCCHresource.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that PUCCHtransmission including the feedback message may be to be transmitted tomultiple TRPs of the set of TRPs based on the QCL information indicatingthat the PUCCH resource may have a QCL relationship with a set ofdifferent downlink reference signals.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining atransmission power for a PUCCH transmission including the feedbackmessage based on a path-loss calculation using a first downlinkreference signal of the set of different downlink reference signals thatexperienced a larger path loss and transmit the PUCCH transmissionincluding the feedback message using the determined transmission power.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining ascrambling identifier corresponding to a TRP of the set of TRPs based onthe at least one indicator and transmitting the feedback message via aPUCCH to the TRP based on the scrambling identifier.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining asemi-persistent schedule configuration for a PDSCH based on theconfiguration message and transmitting a PUCCH transmission once pereach PDSCH occasion based on the semi-persistent schedule configuration.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining asemi-persistent schedule configuration for a PDSCH based on theconfiguration message and transmitting a first PUCCH transmission to afirst TRP of the set of TRPs and a second PUCCH transmission to a secondTRP of the set of TRPs once per each PDSCH occasion, where the firstPUCCH transmission and the second PUCCH transmission include the samefeedback message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first PUCCH transmissionand the second PUCCH transmission may be transmitted in a same timeinterval.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first PUCCH transmissionand the second PUCCH transmission may be transmitted in different timeintervals.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the semi-persistent scheduleconfiguration indicates a first PUCCH resource and a second PUCCHresource per PDSCH occasion and a time offset between the first PUCCHresource and the second PUCCH resource.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the feedbackmessage further may include operations, features, means, or instructionsfor determining, based on the UE operating in a carrier aggregationconfiguration, that information bits for a set of feedback messageincluding the feedback message may be scheduled to be transmitted in asame time interval, multiplexing or bundling the information bits forthe set of feedback message to generate a combined feedback message andtransmitting the combined feedback message. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, may include operations, features, means, orinstructions for determining an ordering of the information bits basedat least in part on a component carrier index and an identifier ofcontrol resource set of a PDCCH resource used to transmit the DCI thatschedules the information bits.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining that anordering of the information bits based on a carrier index and anidentifier of a PDCCH resource used to transmit the DCI that schedulesthe information bits.

A method of wireless communication at a base station is described. Themethod may include transmitting a configuration message for configuringa UE to communicate coordinated transmissions with a set of TRPs using afirst coordinated transmission mode of a set of different coordinatedtransmission modes, transmitting, based on the configuration message,DCI including at least one indicator, and receiving, in accordance witha feedback configuration corresponding to the at least one indicator andthe first coordinated transmission mode, a feedback message for a firstcoordinated transmission.

An apparatus for wireless communication at a base station is described.The apparatus may include a processor, memory in electroniccommunication with the processor, and instructions stored in the memory.The instructions may be executable by the processor to cause theapparatus to transmit a configuration message for configuring a UE tocommunicate coordinated transmissions with a set of TRPs using a firstcoordinated transmission mode of a set of different coordinatedtransmission modes, transmit, based on the configuration message, DCIincluding at least one indicator, and receive, in accordance with afeedback configuration corresponding to the at least one indicator andthe first coordinated transmission mode, a feedback message for a firstcoordinated transmission.

Another apparatus for wireless communication at a base station isdescribed. The apparatus may include means for transmitting aconfiguration message for configuring a UE to communicate coordinatedtransmissions with a set of TRPs using a first coordinated transmissionmode of a set of different coordinated transmission modes, transmitting,based on the configuration message, DCI including at least oneindicator, and receiving, in accordance with a feedback configurationcorresponding to the at least one indicator and the first coordinatedtransmission mode, a feedback message for a first coordinatedtransmission.

A non-transitory computer-readable medium storing code for wirelesscommunication at a base station is described. The code may includeinstructions executable by a processor to transmit a configurationmessage for configuring a UE to communicate coordinated transmissionswith a set of TRPs using a first coordinated transmission mode of a setof different coordinated transmission modes, transmit, based on theconfiguration message, DCI including at least one indicator, andreceive, in accordance with a feedback configuration corresponding tothe at least one indicator and the first coordinated transmission mode,a feedback message for a first coordinated transmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the feedback message may bereceived from the UE.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the feedback message may bereceived from a second base station via a backhaul link.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a number ofinformation bits for the feedback indicator and a number of PUCCHtransmissions in which the UE may be to transmit the feedback message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the at least one indicatorincludes a DAI indicator, a feedback resource indicator, a feedback gapindicator, or any combination thereof.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting the firstcoordinated transmission in accordance with the first coordinatedtransmission mode.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving an indicationthat a second base station transmitted the first coordinatedtransmission in accordance with the first coordinated transmission mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 through 5 illustrate examples of wireless communications systemsthat supports feedback design for multi-transmission reception point(multi-TRP) transmission in accordance with aspects of the presentdisclosure.

FIG. 6 illustrates an example of a quasi co-location (QCL) associationconfiguration that supports feedback design for multi-TRP transmissionin accordance with aspects of the present disclosure.

FIG. 7 illustrates an example of a process flow that supports feedbackdesign for multi-TRP transmission in accordance with aspects of thepresent disclosure.

FIGS. 8 and 9 show block diagrams of devices that support feedbackdesign for multi-TRP transmission in accordance with aspects of thepresent disclosure.

FIG. 10 shows a block diagram of a communications manager that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure.

FIG. 11 shows a diagram of a system including a device that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure.

FIGS. 12 and 13 show block diagrams of devices that support feedbackdesign for multi-TRP transmission in accordance with aspects of thepresent disclosure.

FIG. 14 shows a block diagram of a communications manager that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure.

FIG. 15 shows a diagram of a system including a device that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure.

FIGS. 16 through 20 show flowcharts illustrating methods that supportfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure.

DETAILED DESCRIPTION

The described techniques relate to improved methods, systems, devices,or apparatuses that support feedback design for multi-transmissionreception point (multi-TRP) transmission. Generally, the describedtechniques provide for coordinating communication between a set oftransmission reception points (TRPs) and a user equipment (UE) thatenables the UE to identify a configuration to use for transmittingfeedback to at least one of the TRPs based on downlink control signalingand a coordinated transmission mode in which the UE is configured tooperate.

In an example, a first TRP of the set of TRPs may transmit aconfiguration message for configuring a UE to communicate coordinatedtransmissions with the set of TRPs using a first coordinatedtransmission mode of a set of different coordinated transmission modes.Each coordinated transmission mode may indicate a number of uplink anddownlink control channels and a number of uplink and downlink datachannels configured for communication between a particular TRP and theUE. The first TRP may transmit, based on the configuration message,downlink control information (DCI) that includes at least one indicatorand a grant of resources for a downlink coordinated transmission fromone of the TRPs to the UE.

In some cases, the DCI may include a downlink assignment index (DAI)indicator, an acknowledgment (ACK) or negative acknowledgment (NACK)(e.g., ACK/NACK) resource indicator (ARI), and a feedback gap indicator(e.g., a K1 value) which corresponds to a time gap between a physicaldownlink shared channel (PDSCH) message and when the UE is expected tosend a corresponding physical uplink control channel (PUCCH) messagecarrying a feedback message for the PDSCH message. Based on thecombination of DAI, ARI, and the feedback gap indicator, the UE maydetermine a feedback configuration for transmitting a feedback message(e.g., a hybrid automatic repeat request (HARD) message such as aHARQ-ACK or HARQ-NACK message) within a PUCCH message. The feedbackconfiguration may indicate the number of ACK/NACK bits in the feedbackmessage, the number of PUCCH resources allocated for reporting ACK/NACKfeedback, the number of TRPs, to which TRPs the UE is to transmit thefeedback message, or any combination thereof.

The UE may monitor the resources indicated in the grant and receive thecoordinated transmission communicated in accordance with the configuredtransmission mode. The UE may determine whether it is able tosuccessfully decode the coordinated transmission, and may transmit, inaccordance with the feedback configuration corresponding to the at leastone indicator and the first coordinated transmission mode, the feedbackmessage for the coordinated transmission. According to some aspects, theUE may determine the feedback configuration without the TRP having toincur additional signaling overhead of explicitly indicating thefeedback configuration to the UE.

Particular aspects of the subject matter described herein may beimplemented to realize one or more advantages. The described techniquesmay support improvements in the ACK/NACK feedback framework, decreasingsignaling overhead, and improving reliability, among other advantages.As such, supported techniques may include improved network operationsand, in some examples, may promote network efficiencies, among otherbenefits.

Aspects of the disclosure are initially described in the context ofwireless communications systems. Aspects are then described with respectto a quasi co-location (QCL) association configuration and a processflow. Aspects of the disclosure are further illustrated by and describedwith reference to apparatus diagrams, system diagrams, and flowchartsthat relate to feedback design for multi-TRP transmission.

FIG. 1 illustrates an example of a wireless communications system 100that supports feedback design for multi-TRP transmission in accordancewith aspects of the present disclosure. The wireless communicationssystem 100 includes base stations 105, UEs 115, and a core network 130.In some examples, the wireless communications system 100 may be a LongTerm Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-APro network, or a New Radio (NR) network. In some cases, wirelesscommunications system 100 may support enhanced broadband communications,ultra-reliable (e.g., mission critical) communications, low latencycommunications, or communications with low-cost and low-complexitydevices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. A TRP 105 may be an example of a basestation 105. Base stations 105 described herein may include or may bereferred to by those skilled in the art as a base transceiver station, aradio base station, an access point, a radio transceiver, a NodeB, aneNodeB (eNB), a next-generation Node B or giga-NodeB (either of whichmay be referred to as a gNB), a Home NodeB, a Home eNodeB, or some othersuitable terminology. Wireless communications system 100 may includebase stations 105 of different types (e.g., macro or small cell basestations). The UEs 115 described herein may be able to communicate withvarious types of base stations 105 and network equipment including macroeNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a TRP. In some configurations, various functions of eachaccess network entity or base station 105 may be distributed acrossvarious network devices (e.g., radio heads and access networkcontrollers) or consolidated into a single network device (e.g., a basestation 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 MHz to 300 GHz.Generally, the region from 300 MHz to 3 GHz is known as the ultra-highfrequency (UHF) region or decimeter band, since the wavelengths rangefrom approximately one decimeter to one meter in length. UHF waves maybe blocked or redirected by buildings and environmental features.However, the waves may penetrate structures sufficiently for a macrocell to provide service to UEs 115 located indoors. Transmission of UHFwaves may be associated with smaller antennas and shorter range (e.g.,less than 100 km) compared to transmission using the smaller frequenciesand longer waves of the high frequency (HF) or very high frequency (VHF)portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that can tolerate interference from otherusers.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a carrieraggregation configuration in conjunction with component carriers (CCs)operating in a licensed band (e.g., LAA). Operations in unlicensedspectrum may include downlink transmissions, uplink transmissions,peer-to-peer transmissions, or a combination of these. Duplexing inunlicensed spectrum may be based on frequency division duplexing (FDD),time division duplexing (TDD), or a combination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving devices are equipped with one ormore antennas. MIMO communications may employ multipath signalpropagation to increase the spectral efficiency by transmitting orreceiving multiple signals via different spatial layers, which may bereferred to as spatial multiplexing. The multiple signals may, forexample, be transmitted by the transmitting device via differentantennas or different combinations of antennas. Likewise, the multiplesignals may be received by the receiving device via different antennasor different combinations of antennas. Each of the multiple signals maybe referred to as a separate spatial stream, and may carry bitsassociated with the same data stream (e.g., the same codeword) ordifferent data streams. Different spatial layers may be associated withdifferent antenna ports used for channel measurement and reporting. MIMOtechniques include single-user MIMO (SU-MIMO) where multiple spatiallayers are transmitted to the same receiving device, and multiple-userMIMO (MU-MIMO) where multiple spatial layers are transmitted to multipledevices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g., synchronizationsignals, reference signals, beam selection signals, or other controlsignals) may be transmitted by a base station 105 multiple times indifferent directions, which may include a signal being transmittedaccording to different beamforming weight sets associated with differentdirections of transmission. Transmissions in different beam directionsmay be used to identify (e.g., by the base station 105 or a receivingdevice, such as a UE 115) a beam direction for subsequent transmissionand/or reception by the base station 105. Some signals, such as datasignals associated with a particular receiving device, may betransmitted by a base station 105 in a single beam direction (e.g., adirection associated with the receiving device, such as a UE 115). Insome examples, the beam direction associated with transmissions along asingle beam direction may be determined based at least in in part on asignal that was transmitted in different beam directions. For example, aUE 115 may receive one or more of the signals transmitted by the basestation 105 in different directions, and the UE 115 may report to thebase station 105 an indication of the signal it received with a highestsignal quality, or an otherwise acceptable signal quality. Althoughthese techniques are described with reference to signals transmitted inone or more directions by a base station 105, a UE 115 may employsimilar techniques for transmitting signals multiple times in differentdirections (e.g., for identifying a beam direction for subsequenttransmission or reception by the UE 115), or transmitting a signal in asingle direction (e.g., for transmitting data to a receiving device).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based at least inpart on listening according to different receive beam directions (e.g.,a beam direction determined to have a highest signal strength, highestsignal-to-noise ratio, or otherwise acceptable signal quality based atleast in part on listening according to multiple beam directions).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may insome cases perform packet segmentation and reassembly to communicateover logical channels. A Medium Access Control (MAC) layer may performpriority handling and multiplexing of logical channels into transportchannels. The MAC layer may also use HARQ to provide retransmission atthe MAC layer to improve link efficiency. In the control plane, theRadio Resource Control (RRC) protocol layer may provide establishment,configuration, and maintenance of an RRC connection between a UE 115 anda base station 105 or core network 130 supporting radio bearers for userplane data. At the Physical layer, transport channels may be mapped tophysical channels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems 100, a slot may further bedivided into multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an E-UTRA absolute radiofrequency channel number (EARFCN)), and may be positioned according to achannel raster for discovery by UEs 115. Carriers may be downlink oruplink (e.g., in an FDD mode), or be configured to carry downlink anduplink communications (e.g., in a TDD mode). In some examples, signalwaveforms transmitted over a carrier may be made up of multiplesub-carriers (e.g., using multi-carrier modulation (MCM) techniques suchas discrete Fourier transform-spread-orthogonal frequency divisionmultiplexing (DFT-s-OFDM).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information) and control signaling that coordinatesoperation for the carrier. In some examples (e.g., in a carrieraggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that can support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation or multi-carrier operation. A UE 115 may beconfigured with multiple downlink CCs and one or more uplink CCsaccording to a carrier aggregation configuration. Carrier aggregationmay be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhancedCCs (eCCs). An eCC may be characterized by one or more featuresincluding wider carrier or frequency channel bandwidth, shorter symbolduration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than otherCCs, which may include use of a reduced symbol duration as compared withsymbol durations of the other CCs. A shorter symbol duration may beassociated with increased spacing between adjacent subcarriers. Adevice, such as a UE 115 or base station 105, utilizing eCCs maytransmit wideband signals (e.g., according to frequency channel orcarrier bandwidths of 20, 40, 60, 80 MHz) at reduced symbol durations(e.g., 16.67 microseconds). A TTI in eCC may consist of one or multiplesymbol periods. In some cases, the TTI duration (that is, the number ofsymbol periods in a TTI) may be variable.

Wireless communications systems such as an NR system may utilize anycombination of licensed, shared, and unlicensed spectrum bands, amongothers. The flexibility of eCC symbol duration and subcarrier spacingmay allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossthe frequency domain) and horizontal (e.g., across the time domain)sharing of resources.

A first TRP (e.g., a base station 105) of a set of TRPs may transmit aconfiguration message for configuring a UE 115 to communicatecoordinated transmissions with the set of TRPs using a first coordinatedtransmission mode of a set of different coordinated transmission modes.Each coordinated transmission mode may indicate a number of uplink anddownlink control channels and a number of uplink and downlink datachannels configured for communication between a particular TRP and theUE 115. The first TRP may transmit, based on the configuration message,DCI that includes at least one indicator and a grant of resources for adownlink coordinated transmission from one of the TRPs to the UE 115.

In some cases, the DCI may include a DAI indicator, an ARI, and afeedback gap indicator (e.g., a K1 value). Based on the combination ofDAI, ARI, and the feedback gap indicator, the UE 115 may determine afeedback configuration for transmitting a feedback message (e.g., aHARQ-ACK message) within a PUCCH message. The feedback configuration mayindicate the number of ACK/NACK bits in the feedback message, the numberof PUCCH resources allocated for reporting ACK/NACK feedback, the numberof TRPs and to which TRPs the UE 115 is to transmit the feedbackmessage. The UE 115 may monitor the resources indicated in the grant andreceive the coordinated transmission communicated in accordance with theconfigured transmission mode. The UE 115 may determine whether it isable to successfully decode the coordinated transmission, and maytransmit, in accordance with the feedback configuration corresponding tothe at least one indicator and the first coordinated transmission mode,the feedback message for the coordinated transmission.

FIG. 2 illustrates an example of a wireless communications system 200that supports feedback design for multi-TRP transmission in accordancewith aspects of the present disclosure. In some examples, wirelesscommunications system 200 may implement aspects of wirelesscommunications system 100.

In wireless communications system 200, multiple TRPs 105, which may beexamples of base stations 105 of FIG. 1, may be configured tocommunicate with a single UE 115, such as UE 115-a. The TRPs 105 maycommunicate with UE 115-a in a non-coherent manner, for exampleaccording to non-coherent joint transmission (NCJT). The TRPs 105 and UE115-a may establish downlink connections 205 (e.g., downlink connection205-a for TRP 105-a and downlink connection 205-b for TRP 105-b) anduplink connections 210 (e.g., uplink connection 210-a for TRP 105-a anduplink connection 210-b for TRP 105-b) to communicate. Each TRP 105 maybe able to transmit downlink messages (e.g., physical downlink controlchannel (PDCCH) and PDSCH messages) to UE 115-a on a correspondingdownlink connection 205, and UE 115-a may be able to transmit uplinkmessages (e.g., PUCCH messages or physical uplink shared channel (PUSCH)messages) on a corresponding uplink connection 210. TRP 105-a and TRP105-b may each be an example of a base station 105 as described herein.

TRPs 105-a and 105-b may communicate with UE 115-a according to atransmission mode which is coordinated between the TRPs 105. Atransmission mode may refer to a specific configuration for the NCJTwireless communication between UE 115-a and the TRPs 105. A transmissionmode may relate to a number of PDCCH resources or PDSCH resources usedby the TRPs to communicate with UE 115-a, as well as the contents orrepetition configurations for PDCCH and PDSCH messages. For example,according to a first transmission mode, TRP 105-a and TRP 105-b maycollectively transmit one PDCCH message and one PDSCH message. Inanother transmission mode, TRP 105-a and TRP 105-b may collectivelytransmit one PDSCH message and two PDCCH messages, where the PDCCHmessages are duplicates. Examples of transmission modes are illustratedand described in FIGS. 3A through 5.

The TRPs 105 and UE 115-a may signal to each other to coordinate thetransmission mode. For example, the TRPs 105 may transmit configurationmessage indicating which transmission mode is being used. In some cases,the configuration message may be transmitted as part of RRC signaling.In some other examples, UE 115-a may implicitly determine whichtransmission mode is being used. In some cases, the implicitdetermination may be made based on reference signals or informationincluded in DCI. For example, the TRPs 105 may indicate a defined number(e.g., a maximum number) of codewords per PDSCH when configuring thePDSCH resources. Identifying the defined number of codewords per PDSCHmay assist UE 115-a in determining the multi-TRP transmission modes.

TRP 105-a and TRP 105-b may have an ideal or near ideal connection(e.g., backhaul link 134-a), such that there is zero or approximatelyzero delay for communications between TRP 105-a and TRP 105-b when usingthe backhaul link 134-a. Using the backhaul link 134-a, in someexamples, TRP 105-a and TRP 105-b may be able to quickly communicate alarge amount of data (e.g., nearly instantaneously) with a low level ofloss (e.g., nearly lossless). Therefore, the TRPs 105 may be able tocoordinate dynamic signaling via the backhaul link 134-a withoutsignificant overhead or introducing significant latency.

Depending on the configured transmission mode, UE 115-a may havemultiple configurations for reporting ACK/NACK feedback. In some cases,due to the near ideal backhaul link 134-a, a serving TRP 105 may be ableto convey ACK/NACK feedback to other TRPs 105 with minimal or no delay.In some cases, different feedback configurations may include differentnumbers of PUCCH resources allocated for transmitting PUCCH messageswhich include the ACK/NACK feedback. In some cases, different feedbackconfigurations may include different numbers of bits used to convey theACK/NACK information. Some feedback configurations may transmit theACK/NACK feedback to just one TRP 105 (e.g., TRP 105-a or TRP 105-b),where other feedback configurations may transmit the ACK/NACK feedbackto two or more TRPs 105 (e.g., in a broadcast transmission). Therefore,due to the multiple possible configurations for ACK/NACK feedback, UE115-a and the TRPs 105 may implement techniques to establish a frameworkfor ACK/NACK feedback that addresses different transmission modes. Basedon the established framework, the TRPs 105 may be able to signalparameters to the UE 115-a to enable the UE 115-a to determine afeedback configuration for transmitting the ACK/NACK feedback.

TRPs 105 may configure UE 115-a with multiple control resource sets foreach serving cell per slot. Each serving cell may indicate an activebandwidth part (BWP) of the serving cell, corresponding to frequencyresources of the cell which are assigned to UE 115-a. UE 115-a maymonitor for PDCCH messages in one or more PDCCH monitoring occasions.

UE 115-a may receive a PDCCH message on a downlink connection 205 duringa PDCCH monitoring occasion and select an ACK/NACK feedback option basedon indications included in DCI of the PDCCH message. For example, the UE115-a may determine a feedback configuration based on a DAI, an ARI, anda feedback gap indicator (e.g., a K1 value or a PDSCH-to-HARQ timingindicator) which is related to the gap between a PDSCH message and thecorresponding ACK/NACK feedback. Based on the combination of DAI, ARI,and K1, UE 115-a may determine the number of HARQ ACK/NACK informationbits to use and/or the number of PUCCH transmissions to use whenreporting ACK/NACK feedback. The TRPs 105 may communicate over thebackhaul links 134-a to coordinate the DAI/ARI/K1 indications.

In some cases, the TRPs 105 may indicate a defined number (e.g., the maxnumber) of codewords per PDSCH, and the defined number of codewords perPDSCH may correspond to a number of ACK/NACK bits for UE 115-a to use.In some cases, indicating the defined number of codewords may assist UE115-a in distinguishing the different transmission modes (e.g., asdescribed in FIGS. 3-6). In some examples, the TRPs 105 may configure UE115-a with the different transmission modes (e.g., by configuring anumber of PDSCH and PDCCH resources) by RRC signaling.

UE 115-a may also follow a QCL configuration in the PUCCH resourceconfiguration and the ARI in the DCI to determine whether to transmit aPUCCH message containing the ACK/NACK feedback to TRP 105-a or TRP 105-bor whether to broadcast the PUCCH message to both TRP 105-a and TRP105-b. If the PUCCH message is transmitted to just one TRP 105, UE 115-amay determine to which TRP 105 to transmit the PUCCH message. In somecases, a PUCCH resource may be configured to be QCLed with a downlinkreference signal based on spatial domain parameters. If configured, UE115-a may transmit PUCCH messages using the same spatial domain filtersas used for reception of the corresponding downlink reference signal.

If, for example, the PUCCH resource indicated by the ARI is QCLassociated with one downlink reference signal, the feedbackconfiguration may indicate that the UE 115-a is to transmit PUCCHmessage containing ACK/NACK feedback to one TRP 105. If the PUCCHresource is QCL associated with two different downlink reference signalswith different QCL assumptions, the feedback configuration may indicatethat the UE 115-a is to transmit PUCCH message to multiple TRPs 105(e.g., to each of TRP 105-a and TRP 105-b).

In some cases, UE 115-a may be configured with multiple scramblingidentifiers (e.g., configured by an information element such ashoppingid), where each scrambling identifier corresponds to one of themultiple TRPs 105. The scrambling identifier may be used by UE 115-a togenerate a sequence (e.g., a low peak to average power ratio (PAPR)sequence, or a pseudo random sequence) for a PUCCH transmission (e.g., aPUCCH transmission carrying ACK/NACK feedback). The generated sequencemay be used as the demodulation reference signal (DMRS) sequence for thePUCCH transmission (e.g., in formats 1, 2, 3, and 4). Additionally oralternatively, the generated sequence may be used to modulate thepayload of the PUCCH transmission (e.g., in format 0). Utilizingdifferent PUCCH scrambling identifiers (e.g., or different sequences)for PUCCH transmissions from one or more UEs 115 to TRPs 105-a and 105-bmay reduce interference between the UEs 115 and TRPs 105.

According to some aspects, TRP 105-a or TRP 105-b may indicate to UE115-a the scrambling identifier for UE 115-a to use for a PUCCHtransmission. In some implementations, the indication of the scramblingidentifier (e.g., by TRP 105-a or TRP 105-b) may be dynamically signaledin DCI (e.g., using a scrambling identifier indicator in the DCI).Additionally or alternatively, the scrambling identifier may beconfigured for each PUCCH resource and the UE 115-a may determine thescrambling identifier based on the determined PUCCH resource.

In some cases, path-loss computation may follow the downlink referencesignal with a larger path loss. That is, if the PUCCH resource is QCLedwith two downlink reference signals (e.g., reference signals transmittedby different TRPs), then UE 115-a may base a path-loss calculation onthe larger path loss between the two downlink reference signalresources. For example, if a first downlink reference signal has a pathloss of 120 dB, and a second downlink reference signal has path loss of125 dB, then UE 115-a may determine the path loss to be 125 dB. UE 115-amay use the determined path loss to calculate a transmission power for atransmission of a PUCCH message (e.g., to compensate for the path loss).In an example, the UE 115-a may use a larger transmission power if apath loss is larger. If the PUCCH message is to be received (e.g.,correctly) at the two TRPs 105, then UE 115-a compensates for the largerpath loss so that the PUCCH message may be received by each of the TRPs105.

At least one of the TRPs 105 may transmit a configuration message toconfigure UE 115-a with a set of PDCCH monitoring occasions, and theconfiguration message may indicate each PDCCH monitoring occasion usinga search space identifier and a control resource set identifier. In anexample, the UE 115-a supporting multi-TRP may be configured withmultiple control resource sets per serving cell (active BWP) per slot.In some examples, different control resource sets may have different QCLassumptions to account for PDCCH transmissions from different TRPs 105.In some cases, the PDCCH messages may have an order based on thedifferent PDCCH monitoring occasions. As such, an order of PDCCHmessages may be based on the identifiers of control resource sets inwhich the PDCCH messages are received.

In an example, PDCCH message coming from different TRPs 105 may appearin different PDCCH monitoring occasions, and the different PDCCHmonitoring occasions may have an order. For example, if two PDCCHmessages are received in a same slot, one of the PDCCH messages may bethe “first” PDCCH message and the other PDCCH message may be the“second” PDCCH message based on in which of the control resource setsthe PDCCH messages are received. The order of the PDCCH messagesreceived in a same slot may not be based on a temporal order ofreception and instead may be based on in which PDCCH monitoring occasiona particular PDCCH message is received. For example, the “first” PDCCHmessage may be received in later occurring symbol periods than the“second” PDCCH message. In some cases, UE 115-a, TRP 105-a, and TRP105-b may agree on a number of PDCCH messages (e.g., K PDCCH messages)that can be received at UE 115-a per serving cell per slot as part of UEcapability, which may reduce UE implementation complexity. For example,UE 115-a may be configured to receive at most two PDCCH messages perserving cell per slot.

FIGS. 3A and 3B illustrate respective examples of wirelesscommunications systems 300 and 301 that support feedback design formulti-TRP transmission in accordance with aspects of the presentdisclosure. In some examples, the wireless communications systems 300and 301 may implement aspects of wireless communications systems 100 or200.

Wireless communications system 300 may support a first transmission modefor NCJT communications between UE 115-b, TRP 105-c, and TRP 105-d. Inthe first transmission mode, the TRPs 105 may collectively transmit onePDCCH message and one PDSCH message (e.g., Mode 1: 1 PDCCH+1 PDSCH). Forexample, TRP 105-c may transmit the PDCCH message 305-a to UE 115-b. TRP105-c may transmit PDSCH message 310-a on a first spatially multiplexedlayer, and TRP 105-d may transmit the PDSCH message 310-a on a secondspatially multiplexed layer.

Wireless communications system 301 may support a second transmissionmode for NCJT communications between UE 115-c, TRP 105-e, and TRP 105-f.In the second transmission mode, the TRPs 105 may collectively transmittwo PDCCH messages 305 and one PDSCH message 310 (e.g., Mode 2: 2PDCCH+1 PDSCH). For example, TRP 105-e may transmit PDCCH message 305-bto UE 115-c, and TRP 105-f may transmit PDCCH message 305-c to UE 115-c.The second transmission mode may include PDCCH repetition. For example,PDCCH message 305-b and PDCCH message 305-c may be duplicates or copiesof each other. Transmitting PDCCH duplicates may make the PDCCHtransmission more robust and improve the chances of UE 115-csuccessfully receiving at least one copy of the PDCCH message 305. Inthe second transmission mode, either TRP 105-e or TRP 105-f may transmitthe PDSCH message 310. In some cases, TRP 105-e may transmit PDSCHmessage 310-b to UE 115-c. Or, in other examples, TRP 105-d may transmitPDSCH message 310-c to UE 115-c.

In the first and second transmission modes, the PDCCH message 305, whichis repeated in the second transmission mode, may indicate a DAI/ARI/K1for reporting ACK/NACK feedback. The DAI/ARI/K1 may be included in DCIof the PDCCH message 305. One PDSCH message 310 may be transmitted perslot per CC, therefore the number of ACK/NACK bits for UE 115-b and UE115-c to use in reporting feedback may be equal to a defined number(e.g., the maximum number) of codewords scheduled by DCI per PDSCH, orthe number of codewords in the PDSCH message 310. In some cases, thedefined number of codewords scheduled per PDSCH may be indicated by anindicator (e.g., an information element such asmaxNrofCodeWordsScheduledByDCI).

The UEs 115 and TRPs 105 may implement techniques to coordinate aconfiguration for the UEs 115 to report feedback for the PDSCH messages310 based on the transmission mode and DCI included in the PDCCH message305. In some cases, to improve reliability, the TRPs 105 may scheduletwo PUCCH transmissions for the same ACK/NACK bits. For example, in thefirst transmission mode, UE 115-b may transmit a PUCCH message 315-a toTRP 105-c and a PUCCH message 315-b to TRP 105-d. In some cases, thePUCCH message 315-a and PUCCH message 315-b may include the sameACK/NACK bits. In the second transmission mode, UE 115-c may transmit aPUCCH message 315-c to TRP 105-e and a PUCCH message 315-d to TRP 105-f.Similarly, the PUCCH message 315-c and the PUCCH message 315-d mayinclude the same ACK/NACK bits.

In a first example, the PDCCH message 305 may include DCI containing twoARI fields (e.g., ARI field 330-a and ARI field 330-b) which point totwo PUCCH resources within the same slot. Therefore, UE 115-b maytransmit a PUCCH message 315-a to TRP 105-c on a first PUCCH resourceand transmit a PUCCH message 315-b to TRP 105-d on a second PUCCHresource, the PUCCH messages 315 may be transmitted in the same slot.Similarly, UE 115-c may transmit a PUCCH message 315-c to TRP 105-e on afirst PUCCH resource and transmit a PUCCH message 315-d to TRP 105-f ona second PUCCH resource within the same slot. In some cases, the twoPUCCH messages 315 may be transmitted within a different TTI, such as amini-slot.

In a second example, by configuration, one PUCCH resource may includetwo resources (e.g., time domain resources, frequency domain resources,-code domain resources, or any combination thereof) with different QCLinformation. For example, the different QCL information may indicatedifferent transmit/receive beam directions. In some cases, a firsttransmit/receive beam may point to a first TRP 105 (e.g., TRP 105-c orTRP 105-e) and a second transmit/receive beam may point to a second TRP105 (e.g., TRP 105-d or TRP 105-f, respectively). UE 115-c may transmitPUCCH messages 315 containing the ACK/NACK feedback on both of thetime-frequency-code domain resources. For example, UE 115-c may transmitPUCCH message 315 on a first time-frequency-code domain resource basedon a first QCL association and on a second time-frequency-code domainresource based on a second QCL association. In some cases, DCI in thePDCCH messages 305 may use one DAI and one K1 field to indicate the twotime-frequency-code domain resources.

In a third example, an ARI in the DCI may point to two separate PUCCHresources in which the UE 115 is to transmit a PUCCH message including afeedback message. For example, ARI=k may point to PUCCH resources 2 kand 2 k+1. In some cases, RRC signaling may configure the UE 115 to havethe ARI point to two separate PUCCH resources.

In some cases, PDSCH messages 310 may be scheduled semi-persistently(e.g., via semi-persistent scheduling (SPS)). For example, one PDSCHmessage may be transmitted per slot per downlink SPS configuration. Insome cases, the PDSCH message may be transmitted from different TRPs105, such as the TRPs 105 shown in the wireless communications system300 implementing the first transmission mode (e.g., Mode 1) or thewireless communications system 301 implementing the second transmissionmode (e.g., Mode 2). In some examples under the SPS configuration, theTRPs 105 may configure the UE 115 to transmit one PUCCH message 315 perPDSCH message 310.

In other examples under the SPS configuration, the TRPs 105 mayconfigure the UE 115 to transmit two PUCCH messages 315 per PDSCHmessage 310, where each PUCCH message 315 is targeted toward one TRP105. For example, UE 115-c may transmit PUCCH message 315-c to TRP 105-eand PUCCH message 315-d to TRP 105-f as feedback for an SPS PDSCHmessage (e.g., PDSCH message 310-a or 310-b).

In a first example under the SPS configuration, the PUCCH messages 315may be transmitted in the same slot. For example, the PUCCH messages 315may be TDMed within the slot. The TRPs 105 may configure two PUCCHresources in one SPS configuration. In some cases, the K1 value and thePUCCH resources may be signaled in the SPS-activating DCI.

In a second example under the SPS configuration, the PUCCH messages 315may be transmitted in different slots. The TRPs 105 may configure twoPUCCH resources in one SPS configuration. The TRPs 105 may alsoconfigure a time-domain offset 325 of the second PUCCH resource withrespect to the first PUCCH resource (e.g., in the unit of number ofslots). For example, as shown, the time-domain offset 325 separatesPUCCH message 315-c from PUCCH message 315-d in the time-domain. ThePUCCH message 315-c and PUCCH message 315-d may be transmitted in a sameBWP 320. In some cases, the time-domain offset 325 is referred to asΔ_(k). The SPS-activating DCI may signal a K1 for the first PUCCHmessage (e.g., PUCCH message 315-c), and the actual K1 value for thesecond PUCCH message (e.g., PUCCH message 315-d) may be the value of thetime-domain offset 325 in addition to K1 (e.g., Δ_(k)+K1).

FIG. 4 illustrates an example of a wireless communications system 400that supports feedback design for multi-TRP transmission in accordancewith aspects of the present disclosure. In some examples, wirelesscommunications system 400 may implement aspects of wirelesscommunications systems 100, 200, 300, or 301 for communications betweenUE 115-d, TRP 105-g, and TRP 105-h.

In the third transmission mode, as illustrated in FIG. 4, the TRPs 105may collectively transmit two PDCCH messages 405 and two PDSCH messages410 (e.g., Mode 3: 2 PDCCH+2 PDSCH (Same codeword)). The PDCCH messages405 may schedule the PDSCH messages 410, and the two PDSCH messages 410(e.g., PDSCH message 410-a and PDSCH message 410-b) may include the sameset of at least one codeword. Each codeword may correspond to onetransport block generated at a higher layer (e.g., the MAC layer) at theTRP 105. For example, PDCCH message 405-a may schedule PDSCH message410-a, and PDCCH message 405-b may schedule PDSCH message 410-b. Thethird transmission mode may be an example of PDSCH repetition.

As shown, TRP 105-g may transmit PDCCH message 405-a to UE 115-d, andTRP 105-h may transmit PDCCH message 405-b to UE 115-d. In someexamples, PDCCH message 405-a and PDCCH message 405-b may be transmittedin the same slot to UE 115-d. The PDCCH messages 405 may schedule acorresponding PDSCH message 410 from the TRP 105. TRP 105-g may transmitPDSCH message 410-a to UE 115-d, and TRP 105-h may transmit PDSCHmessage 410-b to UE 115-d, where PDSCH message 410-a and PDSCH message410-b carry the same set of at least one codeword. The PDSCH messages410 may also include a same set of at least one feedback processidentifier (e.g., have a same HARQ process identifier). Each of the setof at least one feedback process identifier corresponds to one codewordin the at least one codeword. In some examples, the PDSCH messages 410may have different resource allocations, modulation coding scheme (MCS)configurations, or redundancy versions, for example to adapt to thedifferent channel condition between the different TRPs 105 and the UE115.

In a first example of an ACK/NACK feedback configuration under the thirdtransmission mode, PDCCH message 405-a and PDCCH message 405-b mayinclude the same K1 value and same ARI. If the PDCCH messages includethe same K1 and ARI parameters, UE 115-d may transmit one PUCCH message415. For example, UE 115-d may transmit either PUCCH message 415-a toTRP 105-g or transmit PUCCH message 415-b to TRP 105-h or transmit thesame PUCCH message 415 to both TRP 105-g and TRP 105-h. The number ofACK/NACK bits included in the PUCCH message 415 may be equal to adefined number (e.g., a threshold number, a maximum number) of codewordsscheduled by DCI. For example, the number of ACK/NACK bits may be basedon the number of codewords which are duplicated in PDSCH message 410-aand 410-b.

In a second example of an ACK/NACK feedback configuration under thethird transmission mode, the PDCCH messages 405 may include either adifferent K1 or a different ARI. In the second example, UE 115-d maytransmit two PUCCH messages 415. Each PUCCH message 415 may follow theK1 and ARI received in a corresponding DCI for PUCCH transmission.

There may be differences in how UE 115-d reports feedback based onwhether the K1 is different or the ARI is different. If the K1 is thesame but the ARI is different, UE 115-d may implement PUCCH repetition.For example, PUCCH message 415-a to TRP 105-g and PUCCH message 415-b toTRP 105-h may be the same PUCCH message 415. If the K1 is different, twodifferent PUCCH messages 415 may be transmitted (e.g., having differentACK/NACK payload) due to ACK/NACK multiplexing and/or bundling acrossslots and across CCs.

For example, UE 115-d may determine to multiplex or bundle HARQ-ACKinformation bits corresponding to multiple PDSCH messages 410 fortransmission in a single PUCCH message 415, and the determination may bebased on where the K1 in two PDCCH messages 405 are the same.Multiplexing may refer to combining feedback for multiple PDSCH messages410 for sending in a single PUCCH message 415. For example, if a UE115-d determines a NACK for a first PDSCH message 410-a and an ACK forsecond PDSCH message 410-b, UE 115-d may transmit a 2-bit sequenceindicating a NACK and an ACK (e.g., ‘01’ where 0 indicates NACK and 1indicates ACK) to the TRP 105. Bundling may refer to the UE 115-dperforming a logical AND operation on two HARQ-ACK information bits, andtransmitting 1 bit to one or more TRPs 105. For example, if UE 115-ddetermines a NACK for a first PDSCH message 410-a and an ACK for secondPDSCH message 410-b, then UE 115-d may transmit 1 bit NACK (e.g., (NACK)AND (ACK)=NACK) to the TRP 105. The TRP 105 may provide a configurationmessage to configure whether the UE 115-d performs multiplexing orbundling. UE 115-d may determine whether to perform multiplexing orbundling based on a configuration message received from the TRP 105containing this information.

In some examples, for any of the transmission modes described herein, UE115-d may multiplex the HARQ-ACK information bits corresponding to otherPDSCH messages 410 received in another slot or component carrier withthe current HARQ-ACK information bits, if the PDCCH messages 405 thatschedule these PDSCH messages 410 indicate that corresponding HARQ-ACKbits are going to be transmitted in the same slot. For example, thetechniques described herein may be applied for carrier aggregation whenused in combination with multi-TRP transmission.

In the third transmission mode (e.g., Mode 3), if UE 115-d successfullydecodes one PDSCH message 410-a, UE 115-d may skip decoding the otherPDSCH message 410-b (or vice versa) because each PDSCH message 410includes the same codeword. However, UE 115-d may still transmit twoPUCCH messages 415 if the two PDCCH messages 405 indicate differentvalues for K1 or ARI.

FIG. 5 illustrates an example of a wireless communications system 500that supports feedback design for multi-TRP transmission in accordancewith aspects of the present disclosure. In some examples, wirelesscommunications system 500 may implement aspects of wirelesscommunications systems 100, 200, 300, 301, or 400.

Wireless communications system 500 may support a fourth transmissionmode for NCJT communications between UE 115-e, TRP 105-i, and TRP 105-j.In the fourth transmission mode, the TRPs 105 may collectively transmittwo PDCCH messages 505 and two PDSCH messages 510 (e.g., Mode 4: 2PDCCH+2 PDSCH (different codewords)). The PDCCH messages 505 mayschedule the PDSCH messages 510. For example, PDCCH message 505-a mayschedule PDSCH message 510-a, and PDCCH message 505-b may schedule PDSCHmessage 510-b. In the fourth transmission mode, the two PDSCH messages510 (e.g., PDSCH message 510-a and PDSCH message 510-b) may includedifferent codewords and HARQ process identifiers. Each codewordcorresponds to one transport block generated at the higher layer (e.g.,the MAC layer) at the base station, and one HARQ process identifier.

As shown, TRP 105-i may transmit PDCCH message 505-a to UE 115-e, andTRP 105-j may transmit PDCCH message 505-b to UE 115-e. TRP 105-i maytransmit PDSCH message 510-a to UE 115-e, and TRP 105-j may transmitPDSCH message 510-b to UE 115-e, where PDSCH message 510-a and PDSCHmessage 510-b carry different codewords with different HARQ processidentifiers.

In a first example of an ACK/NACK feedback configuration under thefourth transmission mode, PDCCH message 505-a and PDCCH message 505-bmay indicate the same K1 value. If the K1 values are the same, UE 115-emay transmit one PUCCH message, where the number of ACK/NACK bitscorrespond to the total number of codewords scheduled by both PDCCHmessage 505-a and PDCCH message 505-b. For example, UE 115-e maytransmit PUCCH message 515-a to TRP 105-i, or UE 115-e may transmitPUCCH message 515-b to TRP 105-j, or UE 115-e may transmit one PUCCHmessage 515 to both TRP 105-i and TRP 105-j. In this first example, UE115-e may use the DAI and ARI that corresponds to the last PDCCHmonitoring occasion for PUCCH transmission and ACK/NACK multiplexing.The last PDCCH monitoring occasion may be based on the control resourceset identifier of the PDCCH monitoring occasion as described in FIG. 2.In some examples, to determine the last PDCCH monitoring occasion, aconfiguration message transmitted by the TRP 105-i configuration maydefine an ordering of the PDCCH monitoring occasions received within oneslot and one cell, where the PDCCH message transmitted within the PDCCHmonitoring occasions may be transmitted by different TRPs 105.

UE 115-e may bundle or multiplex the ACK/NACK feedback results based onwhether the feedback gap indicators (e.g., K1 or the PDSCH-to-HARQtiming indicator) in PDCCH message 505-a and PDCCH message 505-b are thesame. For example, if UE 115-e determined NACK for PDSCH message 510-aand ACK for PDSCH message 510-b, UE 115-e may report “NACK,ACK” (e.g.,two bits) in the PUCCH message 515 to the TRPs 105 in case of ACK-NACKmultiplexing. Additionally, or alternatively, UE 115-e may take thelogical AND operation of the HARQ feedback results and transmit one bitto the TRP 105 in case of ACK-NACK bundling. For example, if PDSCHmessage 510-a were NACK and PDSCH message 510-b were ACK, UE 115-e wouldreport NACK (e.g., (NACK) AND (ACK)=NACK) to the TRPs 105. The UEdetermines whether an ACK/NACK multiplexing should be performed or anACK/NACK bundling should be performed based on the RRC configurationmessage UE 115-e received from the TRPs 105.

In a second example of an ACK/NACK feedback configuration under thefourth transmission mode, PDCCH message 505-a and PDCCH message 505-bmay indicate different K1 values. If the K1 values are different, UE115-e may transmit two PUCCH messages 515. For this second example, thenumber of ACK/NACK bits in each PUCCH message 515 may be based on thenumber of codewords scheduled by a corresponding PDCCH message 505. EachPUCCH message 515 may follow the DAI and ARI received in a correspondingPDCCH message 505 for transmission and ACK/NACK multiplexing.

In some cases, for the fourth transmission mode, the TRPs 105 mayconfigure a parameter corresponding to the maximum number of codewordsscheduled by one DCI (e.g., maxNrofCodeWordsScheduledByDCI) to be equalto ‘1’ to reduce the UE detection complexity. For example, if UE 115-edetects that this parameter has a value of ‘1,’ UE 115-e may determinethe wireless communications system 500 is operating under the fourthtransmission mode. In some cases, each PDSCH message 510 may include onecodeword. For example, if two PDSCH messages 510 are scheduled withinone slot, then each PDSCH message 510 may contain one codeword, or theDCI included in the PDCCH messages 505 may schedule one codeword.

FIG. 6 illustrates an example of a QCL association configuration 600that supports feedback design for multi-TRP transmission in accordancewith aspects of the present disclosure. In some examples, QCLassociation configuration 600 may implement aspects of wirelesscommunications systems 100, 200, 300, 301, 400, or 500.

PUCCH resources may be configured to be QCL associated with a downlinkreference signal based on spatial domain parameters. For example, ifconfigured, UE 115-f may transmit a PUCCH message using the same spatialdomain filters as used for a reception of a corresponding,QCL-associated downlink reference signal. In some cases, a PUCCHresource may be configured to be QCL associated with one downlinkreference signal. The QCL association may be based on a parameterPUCCH-SpatialRelationInfo. In some other examples, a PUCCH resource maybe QCL associated with two different downlink reference signals withdifferent QCL assumptions, where each downlink reference signal istransmitted from one different TRP.

UE 115-f may follow the QCL configuration in the PUCCH resourceconfiguration and ARI to determine whether a PUCCH message istransmitted to either TRP 105-k or TRP 105-l, or whether the PUCCHmessage is broadcasted to both TRP 105-k and TRP 105-l. In some cases,techniques described for the QCL association configuration 600 may beapplied to the transmission modes described herein.

In a first example, the PUCCH resource indicated by ARI is QCLassociated with one downlink reference signal, and hence UE 115-f maytransmit a PUCCH message to a single TRP 105. For example, the PUCCHresource may be QCL associated with a downlink reference signaltransmitted by TRP 105-k on beam 605, or the PUCCH resource may be QCLassociated with a downlink reference signal transmitted by TRP 105-l onbeam 610. UE 115-f may transmit the PUCCH message on either beam 615,which corresponds to beam 605 and the downlink reference signal from TRP105-k, or UE 115-f may transmit the PUCCH message on beam 620, whichcorresponds to beam 610 and the downlink reference signal from TRP105-l.

In a second example, the PUCCH resource indicated by ARI may be QCLassociated with two different downlink reference signals with differentQCL assumptions, and hence UE 115-f may infer that it is to transmit thePUCCH message to multiple TRPs. In the second example, UE 115-f maytransmit the PUCCH message simultaneously to both TRPs 105. In thisexample, the path loss computation may follow the downlink referencesignal with a larger path loss. Based on using the larger path loss, UE115-f may transmit the PUCCH using a larger transmission power comparedto the transmission power that would be used for the smaller path lossso that the PUCCH message may be correctly received by each of the TRPs.

In some cases, UE 115-f may be configured with multiple scramblingidentifiers (e.g., configured by an information element such ashoppingid), where each scrambling identifier corresponds to one of themultiple TRPs 105. The scrambling identifier may be used by UE 115-f togenerate a sequence (e.g., a low PAPR sequence, or a pseudo randomsequence) for a PUCCH transmission (e.g., a PUCCH transmission carryingACK/NACK feedback). The generated sequence may be used as the DMRSsequence for the PUCCH transmission (e.g., in formats 1, 2, 3, and 4).Additionally or alternatively, the generated sequence may be used tomodulate the payload of the PUCCH transmission (e.g., in format 0).Utilizing different PUCCH scrambling identifiers (e.g., or differentsequences) for PUCCH transmissions from one or more UEs 115 to TRPs105-k and 105-l may reduce interference between the UEs 115 and TRPs105.

According to some aspects, TRP 105-k or TRP 105-l may indicate to UE115-f the scrambling identifier for UE 115-f to use for a PUCCHtransmission. In some implementations, the indication of the scramblingidentifier (e.g., by TRP 105-k or TRP 105-l) may be dynamically signaledin DCI (e.g., using a scrambling identifier indicator in the DCI).Additionally or alternatively, the scrambling identifier may beconfigured for each PUCCH resource and the UE 115-f may determine thescrambling identifier based on the determined PUCCH resource.

FIG. 7 illustrates an example of a process flow 700 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. In some examples, process flow 700 may implementaspects of wireless communications systems 100, 200, 300, 301, 400, 500,or 600.

At 705, UE 115-g may receive a configuration message, transmitted by TRP105-m, configuring UE 115-g to communicate coordinated transmissionswith multiple TRPs 105 using a first coordinated transmission mode of aset of different coordinated transmission modes. For example, the set ofdifferent coordinated transmission modes may include the first throughfourth transmission modes described in FIGS. 3A, 3B, 4, and 5.

At 710, UE 115-g may receive, based on the configuration message, DCIincluding at least one indicator from TRP 105-m. The DCI may betransmitted in a PDCCH message. The at least one indicator may include,for example, a DAI, a feedback resource indicator, a feedback gapindicator, or any combination thereof.

At 715, UE 115-g may receive a first coordinated transmissioncommunicated in accordance with the first coordinated transmission mode.In some cases, the first coordinated transmission may be transmitted asa PDSCH message. In some cases, the TRP 105-m, of the set of TRPs, whichtransmits the first coordinated message may be determined based on thecoordinated transmission mode.

At 720, UE 115-g may transmit, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one TRP 105-m of the set of TRPs.For example, if TRP 105-m is connected to another TRP 105 via an idealbackhaul link, UE 115-g may in some cases transmit the feedback messageto the other TRP 105, and the other TRP 105 may convey the feedbackmessage to TRP 105-m via the ideal backhaul link.

FIG. 8 shows a block diagram 800 of a device 805 that supports feedbackdesign for multi-TRP transmission in accordance with aspects of thepresent disclosure. The device 805 may be an example of aspects of a UE115 as described herein. The device 805 may include a receiver 810, acommunications manager 815, and a transmitter 820. The device 805 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 810 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to feedbackdesign for multi-TRP transmission). Information may be passed on toother components of the device 805. The receiver 810 may be an exampleof aspects of the transceiver 1120 described with reference to FIG. 11.The receiver 810 may utilize a single antenna or multiple antennas.

The communications manager 815 may receive a configuration messageconfiguring the UE to communicate coordinated transmissions with a setof TRPs using a first coordinated transmission mode of a set ofdifferent coordinated transmission modes, receive, based on theconfiguration message, DCI including at least one indicator, receive afirst coordinated transmission communicated in accordance with the firstcoordinated transmission mode, and transmit, in accordance with afeedback configuration corresponding to the at least one indicator andthe first coordinated transmission mode, a feedback message for thefirst coordinated transmission to at least one of the set of TRPs. Thecommunications manager 815 may be an example of aspects of thecommunications manager 1110 described herein.

The communications manager 815, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 815, or itssub-components may be executed by a general-purpose processor, a digitalsignal processor (DSP), an application-specific integrated circuit(ASIC), a field-programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed in the present disclosure.

The communications manager 815, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 815, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 815, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

The transmitter 820 may transmit signals generated by other componentsof the device 805. In some examples, the transmitter 820 may becollocated with a receiver 810 in a transceiver module. For example, thetransmitter 820 may be an example of aspects of the transceiver 1120described with reference to FIG. 11. The transmitter 820 may utilize asingle antenna or multiple antennas.

In some examples, the communications manager 815 may be implemented asan integrated circuit or chip set for a mobile device modem, and thereceiver 810 and transmitter 820 may be implemented as analog components(e.g., amplifiers, filters, antennas) coupled with the mobile devicemodem to enable wireless transmission and reception over one or morebands.

The communications manager 815 as described herein may be implemented torealize one or more potential advantages. One implementation may allowthe device 805 to more efficiently coordinate communication between aset of TRPs and the device 805, and more specifically to coordinatefeedback communication from the device 805 to one or more TRPs. Forexample, the device 805 may identify a configuration to use fortransmitting feedback to a TRP, based on received downlink controlsignaling and a coordinated transmission mode.

Based on implementing the feedback mechanism techniques as describedherein, a processor of a UE 115 (e.g., controlling the receiver 810, thetransmitter 820, or the transceiver 1120 as described with reference toFIG. 11) may increase reliability and decrease signaling overhead in thecommunication of feedback because the feedback configuration may not beexplicitly indicated to the UE 115.

FIG. 9 shows a block diagram 900 of a device 905 that supports feedbackdesign for multi-TRP transmission in accordance with aspects of thepresent disclosure. The device 905 may be an example of aspects of adevice 805 or a UE 115 as described herein. The device 905 may include areceiver 910, a communications manager 915, and a transmitter 940. Thedevice 905 may also include a processor. Each of these components may bein communication with one another (e.g., via one or more buses).

The receiver 910 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to feedbackdesign for multi-TRP transmission). Information may be passed on toother components of the device 905. The receiver 910 may be an exampleof aspects of the transceiver 1120 described with reference to FIG. 11.The receiver 910 may utilize a single antenna or multiple antennas.

The communications manager 915 may be an example of aspects of thecommunications manager 815 as described herein. The communicationsmanager 915 may include a transmission mode configuration component 920,a DCI indicator component 925, a coordinated transmission component 930,and a feedback component 935. The communications manager 915 may be anexample of aspects of the communications manager 1110 described herein.

The transmission mode configuration component 920 may receive aconfiguration message configuring the UE to communicate coordinatedtransmissions with a set of TRPs using a first coordinated transmissionmode of a set of different coordinated transmission modes. The DCIindicator component 925 may receive, based on the configuration message,DCI including at least one indicator. The coordinated transmissioncomponent 930 may receive a first coordinated transmission communicatedin accordance with the first coordinated transmission mode. The feedbackcomponent 935 may transmit, in accordance with a feedback configurationcorresponding to the at least one indicator and the first coordinatedtransmission mode, a feedback message for the first coordinatedtransmission to at least one of the set of TRPs.

The transmitter 940 may transmit signals generated by other componentsof the device 905. In some examples, the transmitter 940 may becollocated with a receiver 910 in a transceiver module. For example, thetransmitter 940 may be an example of aspects of the transceiver 1120described with reference to FIG. 11. The transmitter 940 may utilize asingle antenna or multiple antennas.

FIG. 10 shows a block diagram 1000 of a communications manager 1005 thatsupports feedback design for multi-TRP transmission in accordance withaspects of the present disclosure. The communications manager 1005 maybe an example of aspects of a communications manager 815, acommunications manager 915, or a communications manager 1110 describedherein. The communications manager 1005 may include a transmission modeconfiguration component 1010, a DCI indicator component 1015, acoordinated transmission component 1020, a feedback component 1025, amultiplexing component 1030, a QCL component 1035, a SPS component 1040,and a carrier aggregation component 1045. Each of these modules maycommunicate, directly or indirectly, with one another (e.g., via one ormore buses).

The transmission mode configuration component 1010 may receive aconfiguration message configuring the UE to communicate coordinatedtransmissions with a set of TRPs using a first coordinated transmissionmode of a set of different coordinated transmission modes.

In some examples, the transmission mode configuration component 1010 mayidentify that the configuration message indicates that a PUCCH resourceincludes a first resource having first QCL information and a secondresource having second QCL information, where the feedback message istransmitted via the first resource in accordance with the first QCLinformation and the feedback message is transmitted via the secondresource in accordance with the second QCL information.

The DCI indicator component 1015 may receive, based on the configurationmessage, DCI including at least one indicator. In some cases, the atleast one indicator includes a DAI indicator, a feedback resourceindicator, a feedback gap indicator, or any combination thereof.

In some examples, determining that the at least one indicator includes afeedback resource indicator indicating a first PUCCH resource and asecond PUCCH resource that is different than the first PUCCH resource,where the feedback message is transmitted via the first PUCCH resourceand via the second PUCCH resource.

In some examples, the DCI indicator component 1015 may receive, within asame time interval, a first control channel transmission including theDCI from a first TRP of the set of TRPs and a second control channeltransmission including second DCI from a second TRP of the set of TRPs,the second DCI including a second at least one indicator.

In some examples, the DCI indicator component 1015 may determine, basedon the first coordinated transmission mode, that the first controlchannel transmission schedules the first coordinated transmission andthat the second control channel transmission schedules a secondcoordinated transmission.

In some examples, the DCI indicator component 1015 may determine thatthe first coordinated transmission and the second coordinatedtransmission each include a same at least one codeword and a same atleast one feedback process identifier associated with the at least onecodeword. In some cases, the DCI indicator component 1015 may determinethat a number of information bits in the feedback message is the same asthe number of codewords scheduled by the DCI. In some examples, the DCIindicator component 1015 may determine, based on the first coordinatedtransmission mode, that the first control channel transmission schedulesthe first coordinated transmission and that a second control channeltransmission schedules a second coordinated transmission.

In some examples, the DCI indicator component 1015 may determine thatthe first coordinated transmission and the second coordinatedtransmission each include a different codeword and a different feedbackidentifier associated with each of the different codewords. In somecases, the DCI schedules one or two codewords.

The coordinated transmission component 1020 may receive a firstcoordinated transmission communicated in accordance with the firstcoordinated transmission mode. In some examples, the coordinatedtransmission component 1020 may determine whether to decode the firstcoordinated transmission received from the first TRP based on a decodingdecision for the second coordinated transmission received from thesecond TRP.

The feedback component 1025 may transmit, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one of the set of TRPs. In someexamples, the feedback component 1025 may determine a number ofinformation bits for the feedback message and a number of PUCCHtransmissions in which to transmit the feedback message.

In some examples, the feedback component 1025 may determine that the atleast one indicator includes a first resource indicator indicating afirst PUCCH resource in a time interval and a second resource indicatorindicating a second PUCCH resource in the TTI that is different than thefirst PUCCH resource, where the feedback message is transmitted via eachof the first PUCCH resource and the second PUCCH resource within thetime interval. In some cases, the time interval is a slot or amini-slot.

In some examples, the feedback component 1025 may determine to transmitthe feedback message for the first coordinated transmission and thesecond coordinated transmission in a single PUCCH transmission based ona first feedback gap indicator and a first feedback resource indicatorincluded in the at least one indicator being the same as a secondfeedback gap indicator and a second feedback resource indicator includedin the second at least one indicator.

In some examples, the feedback component 1025 may determine to transmitthe feedback message for the first coordinated transmission and thesecond coordinated transmission in multiple PUCCH transmission based onat least one of a first feedback gap indicator or a first feedbackresource indicator included in the at least one indicator differing froma second feedback gap indicator or a second feedback resource indicatorincluded in the second at least one indicator.

In some examples, the feedback component 1025 may determine to transmitthe feedback message in multiple PUCCH transmissions based on a firstfeedback gap indicator included in the at least one indicator differingfrom a second feedback gap indicator included in the second at least oneindicator.

In some examples, the feedback component 1025 may determine a scramblingidentifier corresponding to a TRP of the set of TRPs based on the atleast one indicator. In some examples, the feedback component 1025 maytransmit the feedback message via a physical uplink control channel tothe TRP based on the scrambling identifier.

The multiplexing component 1030 may determine to multiplex or bundleinformation bits corresponding to each of the first and secondcoordinated transmissions in a single PUCCH transmission based ondetermining that a first feedback gap indicator included in the at leastone indicator is the same as a second feedback gap indicator included inthe second at least one indicator. In some examples, the multiplexingcomponent 1030 may determine to multiplex or bundle information bits isbased on the configuration message.

In some examples, the multiplexing component 1030 may identify afeedback resource for transmitting the feedback message based on afeedback resource indicator and a DAI indicator included in the at leastone indicator associated with a defined monitoring occasion of the setof PDCCH monitoring occasions. In some cases, the ordering of the set ofPDCCH monitoring occasions corresponds to an ordering of a set ofcontrol resource set identifiers indicated in the configuration message.In some cases, each of the set of control resource set identifiers isrespectively associated with the set of PDCCH monitoring occasion, andwhere each control resource set of a set of control resource setscorresponds to one of the set of control resource set identifiers andone of the TRPs.

The QCL component 1035 may determine a PUCCH resource indicated by afeedback resource indicator of the at least one indicator. In someexamples, the QCL component 1035 may identify QCL information for thePUCCH resource. In some examples, the QCL component 1035 may determine anumber of TRPs to which the UE is to transmit the feedback message basedon the QCL information. In some examples, the QCL component 1035 maydetermine that a PUCCH transmission including the feedback message is tobe transmitted to a single TRP of the set of TRPs based on the QCLinformation indicating that the PUCCH resource has a QCL relationshipwith a single downlink reference signal and transmit the feedbackmessage in accordance with the QCL information for the PUCCH resource.

In some examples, the QCL component 1035 may determine that PUCCHtransmission including the feedback message is to be transmitted tomultiple TRPs of the set of TRPs based on the QCL information indicatingthat the PUCCH resource has a QCL relationship with a set of differentdownlink reference signals.

In some examples, the QCL component 1035 may determine a transmissionpower for a PUCCH transmission including the feedback message based on apath-loss calculation using a first downlink reference signal of the setof different downlink reference signals that experienced a larger pathloss and transmit the PUCCH transmission including the feedback messageusing the determined transmission power.

The SPS component 1040 may determine a semi-persistent scheduleconfiguration for a PDSCH based on the configuration message. In someexamples, the SPS component 1040 may transmit a PUCCH transmission onceper each PDSCH occasion based on the semi-persistent scheduleconfiguration. In some cases, the semi-persistent schedule configurationindicates a first PUCCH resource and a second PUCCH resource per PDSCHoccasion and a time offset between the first PUCCH resource and thesecond PUCCH resource.

In some examples, the SPS component 1040 may transmit a first PUCCHtransmission to a first TRP of the set of TRPs and a second PUCCHtransmission to a second TRP of the set of TRPs once per each PDSCHoccasion, where the first PUCCH transmission and the second PUCCHtransmission include the same feedback message. In some cases, the firstPUCCH transmission and the second PUCCH transmission are transmitted ina same time interval. In some cases, the first PUCCH transmission andthe second PUCCH transmission are transmitted in different timeintervals.

The carrier aggregation component 1045 may determine, based on the UEoperating in a carrier aggregation configuration, that information bitsfor a set of feedback message including the feedback message arescheduled to be transmitted in a same time interval. In some examples,the carrier aggregation component 1045 may multiplex or bundle theinformation bits for the set of feedback message to generate a combinedfeedback message. In some examples, the carrier aggregation component1045 may transmit the combined feedback message. In some examples, thecarrier aggregation component 1045 may determine that an ordering of theinformation bits on a carrier index and an identifier of a PDCCHresource used to transmit the DCI that schedules the information bits

FIG. 11 shows a diagram of a system 1100 including a device 1105 thatsupports feedback design for multi-TRP transmission in accordance withaspects of the present disclosure. The device 1105 may be an example ofor include the components of device 805, device 905, or a UE 115 asdescribed herein. The device 1105 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including a communicationsmanager 1110, an I/O controller 1115, a transceiver 1120, an antenna1125, memory 1130, and a processor 1140. These components may be inelectronic communication via one or more buses (e.g., bus 1145).

The communications manager 1110 may receive a configuration messageconfiguring the UE to communicate coordinated transmissions with a setof TRPs using a first coordinated transmission mode of a set ofdifferent coordinated transmission modes, receive, based on theconfiguration message, DCI including at least one indicator, receive afirst coordinated transmission communicated in accordance with the firstcoordinated transmission mode, and transmit, in accordance with afeedback configuration corresponding to the at least one indicator andthe first coordinated transmission mode, a feedback message for thefirst coordinated transmission to at least one of the set of TRPs.

The I/O controller 1115 may manage input and output signals for thedevice 1105. The I/O controller 1115 may also manage peripherals notintegrated into the device 1105. In some cases, the I/O controller 1115may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 1115 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 1115may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 1115may be implemented as part of a processor. In some cases, a user mayinteract with the device 1105 via the I/O controller 1115 or viahardware components controlled by the I/O controller 1115.

The transceiver 1120 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described herein. For example, thetransceiver 1120 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1120 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the device 1105 may include a single antenna 1125, or thedevice 1105 may have more than one antenna 1125, which may be capable ofconcurrently transmitting or receiving multiple wireless transmissions.

The memory 1130 may include random-access memory (RAM) and read-onlymemory (ROM). The memory 1130 may store computer-readable,computer-executable code 1135 including instructions that, whenexecuted, cause the processor to perform various functions describedherein. In some cases, the memory 1130 may contain, among other things,a basic I/O system (BIOS) which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

The processor 1140 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a central processing unit (CPU), amicrocontroller, an ASIC, an FPGA, a programmable logic device, adiscrete gate or transistor logic component, a discrete hardwarecomponent, or any combination thereof). In some cases, the processor1140 may be configured to operate a memory array using a memorycontroller. In other cases, a memory controller may be integrated intothe processor 1140. The processor 1140 may be configured to executecomputer-readable instructions stored in a memory (e.g., the memory1130) to cause the device 1105 to perform various functions (e.g.,functions or tasks supporting feedback design for multi-TRPtransmission).

The code 1135 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1135 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1135 may not be directly executable by theprocessor 1140 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 12 shows a block diagram 1200 of a device 1205 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. The device 1205 may be an example of aspects ofa base station 105 or a TRP 105 as described herein. The device 1205 mayinclude a receiver 1210, a communications manager 1215, and atransmitter 1220. The device 1205 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 1210 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to feedbackdesign for multi-TRP transmission). Information may be passed on toother components of the device 1205. The receiver 1210 may be an exampleof aspects of the transceiver 1520 described with reference to FIG. 15.The receiver 1210 may utilize a single antenna or multiple antennas.

The communications manager 1215 may transmit a configuration message forconfiguring a UE to communicate coordinated transmissions with a set ofTRPs using a first coordinated transmission mode of a set of differentcoordinated transmission modes, transmit, based on the configurationmessage, DCI including at least one indicator, and receive, inaccordance with a feedback configuration corresponding to the at leastone indicator and the first coordinated transmission mode, a feedbackmessage for a first coordinated transmission. The communications manager1215 may be an example of aspects of the communications manager 1510described herein.

The communications manager 1215, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1215, or itssub-components may be executed by a general-purpose processor, a DSP, anASIC, an FPGA or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure.

The communications manager 1215, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1215, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1215, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an I/O component, atransceiver, a network server, another computing device, one or moreother components described in the present disclosure, or a combinationthereof in accordance with various aspects of the present disclosure.

The transmitter 1220 may transmit signals generated by other componentsof the device 1205. In some examples, the transmitter 1220 may becollocated with a receiver 1210 in a transceiver module. For example,the transmitter 1220 may be an example of aspects of the transceiver1520 described with reference to FIG. 15. The transmitter 1220 mayutilize a single antenna or multiple antennas. FIG. 13 shows a blockdiagram 1300 of a device 1305 that supports feedback design formulti-TRP transmission in accordance with aspects of the presentdisclosure. The device 1305 may be an example of aspects of a device1205, a base station 105, or a TRP 105 as described herein. The device1305 may include a receiver 1310, a communications manager 1315, and atransmitter 1335. The device 1305 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 1310 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to feedbackdesign for multi-TRP transmission). Information may be passed on toother components of the device 1305. The receiver 1310 may be an exampleof aspects of the transceiver 1520 described with reference to FIG. 15.The receiver 1310 may utilize a single antenna or multiple antennas.

The communications manager 1315 may be an example of aspects of thecommunications manager 1215 as described herein. The communicationsmanager 1315 may include a transmission mode configuration component1320, a DCI transmitter 1325, and a feedback component 1330. Thecommunications manager 1315 may be an example of aspects of thecommunications manager 1510 described herein.

The transmission mode configuration component 1320 may transmit aconfiguration message for configuring a UE to communicate coordinatedtransmissions with a set of TRPs using a first coordinated transmissionmode of a set of different coordinated transmission modes. The DCItransmitter 1325 may transmit, based on the configuration message, DCIincluding at least one indicator. The feedback component 1330 mayreceive, in accordance with a feedback configuration corresponding tothe at least one indicator and the first coordinated transmission mode,a feedback message for a first coordinated transmission.

The transmitter 1335 may transmit signals generated by other componentsof the device 1305. In some examples, the transmitter 1335 may becollocated with a receiver 1310 in a transceiver module. For example,the transmitter 1335 may be an example of aspects of the transceiver1520 described with reference to FIG. 15. The transmitter 1335 mayutilize a single antenna or multiple antennas.

FIG. 14 shows a block diagram 1400 of a communications manager 1405 thatsupports feedback design for multi-TRP transmission in accordance withaspects of the present disclosure. The communications manager 1405 maybe an example of aspects of a communications manager 1215, acommunications manager 1315, or a communications manager 1510 describedherein. The communications manager 1405 may include a transmission modeconfiguration component 1410, a DCI transmitter 1415, a feedbackcomponent 1420, and a coordinated transmission component 1425. Each ofthese modules may communicate, directly or indirectly, with one another(e.g., via one or more buses).

The transmission mode configuration component 1410 may transmit aconfiguration message for configuring a UE to communicate coordinatedtransmissions with a set of TRPs using a first coordinated transmissionmode of a set of different coordinated transmission modes.

The DCI transmitter 1415 may transmit, based on the configurationmessage, DCI including at least one indicator. In some cases, the atleast one indicator includes a DAI indicator, a feedback resourceindicator, a feedback gap indicator, or any combination thereof.

The feedback component 1420 may receive, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for a firstcoordinated transmission. In some examples, the feedback component 1420may determine a number of information bits for the feedback message anda number of PUCCH transmissions in which the UE is to transmit thefeedback message. In some cases, the feedback message is received fromthe UE. In some cases, the feedback message is received from a secondbase station via a backhaul link.

The coordinated transmission component 1425 may transmit the firstcoordinated transmission in accordance with the first coordinatedtransmission mode. In some examples, the coordinated transmissioncomponent 1425 may receive an indication that a second base stationtransmitted the first coordinated transmission in accordance with thefirst coordinated transmission mode.

FIG. 15 shows a diagram of a system 1500 including a device 1505 thatsupports feedback design for multi-TRP transmission in accordance withaspects of the present disclosure. The device 1505 may be an example ofor include the components of device 1205, device 1305, a TRP 105, or abase station 105 as described herein. The device 1505 may includecomponents for bi-directional voice and data communications includingcomponents for transmitting and receiving communications, including acommunications manager 1510, a network communications manager 1515, atransceiver 1520, an antenna 1525, memory 1530, a processor 1540, and aninter-station communications manager 1545. These components may be inelectronic communication via one or more buses (e.g., bus 1550).

The communications manager 1510 may transmit a configuration message forconfiguring a UE to communicate coordinated transmissions with a set ofTRPs using a first coordinated transmission mode of a set of differentcoordinated transmission modes, transmit, based on the configurationmessage, DCI including at least one indicator, and receive, inaccordance with a feedback configuration corresponding to the at leastone indicator and the first coordinated transmission mode, a feedbackmessage for a first coordinated transmission.

The network communications manager 1515 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 1515 may manage the transferof data communications for client devices, such as one or more UEs 115.

The transceiver 1520 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described herein. For example, thetransceiver 1520 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1520 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the device 1505 may include a single antenna 1525, or thedevice 1505 may have more than one antenna 1525, which may be capable ofconcurrently transmitting or receiving multiple wireless transmissions.

The memory 1530 may include RAM, ROM, or a combination thereof. Thememory 1530 may store computer-readable code 1535 including instructionsthat, when executed by a processor (e.g., the processor 1540) cause thedevice to perform various functions described herein. In some cases, thememory 1530 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1540 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1540 may be configured to operate a memoryarray using a memory controller. In some cases, a memory controller maybe integrated into processor 1540. The processor 1540 may be configuredto execute computer-readable instructions stored in a memory (e.g., thememory 1530) to cause the device 1505 to perform various functions(e.g., functions or tasks supporting feedback design for multi-TRPtransmission).

The inter-station communications manager 1545 may manage communicationswith other base stations 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager1545 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager1545 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The code 1535 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1535 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1535 may not be directly executable by theprocessor 1540 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 16 shows a flowchart illustrating a method 1600 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. The operations of method 1600 may be implementedby a UE 115 or its components as described herein. For example, theoperations of method 1600 may be performed by a communications manageras described with reference to FIGS. 8 through 11. In some examples, aUE may execute a set of instructions to control the functional elementsof the UE to perform the functions described herein. Additionally oralternatively, a UE may perform aspects of the functions describedherein using special-purpose hardware.

At 1605, the UE may receive a configuration message configuring the UEto communicate coordinated transmissions with a set of TRPs using afirst coordinated transmission mode of a set of different coordinatedtransmission modes. The operations of 1605 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1605 may be performed by a transmission mode configurationcomponent as described with reference to FIGS. 8 through 11.

At 1610, the UE may receive, based on the configuration message, DCIincluding at least one indicator. The operations of 1610 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1610 may be performed by a DCI indicatorcomponent as described with reference to FIGS. 8 through 11.

At 1615, the UE may receive a first coordinated transmissioncommunicated in accordance with the first coordinated transmission mode.The operations of 1615 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1615may be performed by a coordinated transmission component as describedwith reference to FIGS. 8 through 11.

At 1620, the UE may transmit, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one of the set of TRPs. Theoperations of 1620 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1620 may beperformed by a feedback component as described with reference to FIGS. 8through 11.

FIG. 17 shows a flowchart illustrating a method 1700 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. The operations of method 1700 may be implementedby a UE 115 or its components as described herein. For example, theoperations of method 1700 may be performed by a communications manageras described with reference to FIGS. 8 through 11. In some examples, aUE may execute a set of instructions to control the functional elementsof the UE to perform the functions described herein. Additionally oralternatively, a UE may perform aspects of the functions describedherein using special-purpose hardware.

At 1705, the UE may receive a configuration message configuring the UEto communicate coordinated transmissions with a set of TRPs using afirst coordinated transmission mode of a set of different coordinatedtransmission modes. The operations of 1705 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1705 may be performed by a transmission mode configurationcomponent as described with reference to FIGS. 8 through 11.

At 1710, the UE may receive, based on the configuration message, DCIincluding at least one indicator. The operations of 1710 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1710 may be performed by a DCI indicatorcomponent as described with reference to FIGS. 8 through 11.

At 1715, the UE may receive a first coordinated transmissioncommunicated in accordance with the first coordinated transmission mode.The operations of 1715 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1715may be performed by a coordinated transmission component as describedwith reference to FIGS. 8 through 11.

At 1720, the UE may determine a number of information bits for thefeedback message and a number of PUCCH transmissions in which totransmit the feedback message. The operations of 1720 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1720 may be performed by a feedback component asdescribed with reference to FIGS. 8 through 11.

At 1725, the UE may transmit, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one of the set of TRPs. Theoperations of 1725 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1725 may beperformed by a feedback component as described with reference to FIGS. 8through 11.

FIG. 18 shows a flowchart illustrating a method 1800 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. The operations of method 1800 may be implementedby a UE 115 or its components as described herein. For example, theoperations of method 1800 may be performed by a communications manageras described with reference to FIGS. 8 through 11. In some examples, aUE may execute a set of instructions to control the functional elementsof the UE to perform the functions described herein. Additionally oralternatively, a UE may perform aspects of the functions describedherein using special-purpose hardware.

At 1805, the UE may receive a configuration message configuring the UEto communicate coordinated transmissions with a set of TRPs using afirst coordinated transmission mode of a set of different coordinatedtransmission modes. The operations of 1805 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1805 may be performed by a transmission mode configurationcomponent as described with reference to FIGS. 8 through 11.

At 1810, the UE may identify that the configuration message indicatesthat a PUCCH resource includes a first resource having first QCLinformation and a second resource having second QCL information, wherethe feedback message is transmitted via the first resource in accordancewith the first QCL information and the feedback message is transmittedvia the second resource in accordance with the second QCL information.The operations of 1810 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1810may be performed by a transmission mode configuration component asdescribed with reference to FIGS. 8 through 11.

At 1815, the UE may receive, based on the configuration message, DCIincluding at least one indicator. The operations of 1815 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1815 may be performed by a DCI indicatorcomponent as described with reference to FIGS. 8 through 11.

At 1820, the UE may receive a first coordinated transmissioncommunicated in accordance with the first coordinated transmission mode.The operations of 1820 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1820may be performed by a coordinated transmission component as describedwith reference to FIGS. 8 through 11.

At 1825, the UE may transmit, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for the firstcoordinated transmission to at least one of the set of TRPs. Theoperations of 1825 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1825 may beperformed by a feedback component as described with reference to FIGS. 8through 11.

FIG. 19 shows a flowchart illustrating a method 1900 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. The operations of method 1900 may be implementedby a TRP 105, a base station 105, or the components of a base station105 or a TRP 105 as described herein. For example, the operations ofmethod 1900 may be performed by a communications manager as describedwith reference to FIGS. 12 through 15. In some examples, a base stationmay execute a set of instructions to control the functional elements ofthe base station to perform the functions described herein. Additionallyor alternatively, a base station may perform aspects of the functionsdescribed herein using special-purpose hardware.

At 1905, the base station may transmit a configuration message forconfiguring a UE to communicate coordinated transmissions with a set ofTRPs using a first coordinated transmission mode of a set of differentcoordinated transmission modes. The operations of 1905 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1905 may be performed by a transmission modeconfiguration component as described with reference to FIGS. 12 through15.

At 1910, the base station may transmit, based on the configurationmessage, DCI including at least one indicator. The operations of 1910may be performed according to the methods described herein. In someexamples, aspects of the operations of 1910 may be performed by a DCItransmitter as described with reference to FIGS. 12 through 15.

At 1915, the base station may receive, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for a firstcoordinated transmission. The operations of 1915 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1915 may be performed by a feedback component asdescribed with reference to FIGS. 12 through 15.

FIG. 20 shows a flowchart illustrating a method 2000 that supportsfeedback design for multi-TRP transmission in accordance with aspects ofthe present disclosure. The operations of method 2000 may be implementedby a TRP 105, a base station 105, or the components of a base station105 or a TRP 105 as described herein. For example, the operations ofmethod 2000 may be performed by a communications manager as describedwith reference to FIGS. 12 through 15. In some examples, a base stationmay execute a set of instructions to control the functional elements ofthe base station to perform the functions described herein. Additionallyor alternatively, a base station may perform aspects of the functionsdescribed herein using special-purpose hardware.

At 2005, the base station may determine a number of information bits forthe feedback message and a number of PUCCH transmissions in which the UEis to transmit the feedback message. The operations of 2005 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2005 may be performed by a feedbackcomponent as described with reference to FIGS. 12 through 15.

At 2010, the base station may transmit a configuration message forconfiguring a UE to communicate coordinated transmissions with a set ofTRPs using a first coordinated transmission mode of a set of differentcoordinated transmission modes. The operations of 2010 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2010 may be performed by a transmission modeconfiguration component as described with reference to FIGS. 12 through15.

At 2015, the base station may transmit, based on the configurationmessage, DCI including at least one indicator. The operations of 2015may be performed according to the methods described herein. In someexamples, aspects of the operations of 2015 may be performed by a DCItransmitter as described with reference to FIGS. 12 through 15.

At 2020, the base station may receive, in accordance with a feedbackconfiguration corresponding to the at least one indicator and the firstcoordinated transmission mode, a feedback message for a firstcoordinated transmission. The operations of 2020 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2020 may be performed by a feedback component asdescribed with reference to FIGS. 12 through 15.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEs115 with service subscriptions with the network provider. A small cellmay be associated with a lower-powered base station 105, as comparedwith a macro cell, and a small cell may operate in the same or different(e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Smallcells may include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs 115 with servicesubscriptions with the network provider. A femto cell may also cover asmall geographic area (e.g., a home) and may provide restricted accessby UEs 115 having an association with the femto cell (e.g., UEs 115 in aclosed subscriber group (CSG), UEs 115 for users in the home, and thelike). An eNB for a macro cell may be referred to as a macro eNB. An eNBfor a small cell may be referred to as a small cell eNB, a pico eNB, afemto eNB, or a home eNB. An eNB may support one or multiple (e.g., two,three, four, and the like) cells, and may also support communicationsusing one or multiple component carriers.

The wireless communications system 100 or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the base stations 105 may have similar frame timing, andtransmissions from different base stations 105 may be approximatelyaligned in time. For asynchronous operation, the base stations 105 mayhave different frame timing, and transmissions from different basestations 105 may not be aligned in time. The techniques described hereinmay be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, a FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude RAM, ROM, electrically erasable programmable ROM (EEPROM), flashmemory, compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include CD, laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication at a userequipment (UE), comprising: receiving a configuration messageconfiguring the UE to communicate coordinated transmissions with aplurality of transmission reception points using a first coordinatedtransmission mode of a plurality of different coordinated transmissionmodes; receiving, based at least in part on the configuration message,downlink control information comprising at least one indicator;receiving a first coordinated transmission communicated in accordancewith the first coordinated transmission mode; and transmitting, inaccordance with a feedback configuration corresponding to the at leastone indicator and the first coordinated transmission mode, a feedbackmessage for the first coordinated transmission to at least one of theplurality of transmission reception points.